How do i turn off individual lights using falloff in animation nodes?
You need to know how to access and modify each light's energy. Then evaluate the falloff in a subprogram and tweak each light's energy.
In order to know the property's name, you have to activate &quot;Python tooltips&quot; in the preferences :

Then hover you cursor over the field :

So, given the point light, you access its energy with an attribute node and the path data.energy. Similarly, if you want to access the color, you would use data.color.

For ease of use put all your lights in their own collection.

Add your falloff object (I chose a cube), tweak the fallof type and connect it to your subprogram.

Result :